Hi -
From: "Brian E Carpenter" <brian(_dot_)e(_dot_)carpenter(_at_)gmail(_dot_)com>
To: "Ned Freed" <ned(_dot_)freed(_at_)mrochek(_dot_)com>
Cc: "John C Klensin" <john-ietf(_at_)jck(_dot_)com>;
<yaronf(_dot_)ietf(_at_)gmail(_dot_)com>; <ietf(_at_)ietf(_dot_)org>
Sent: Tuesday, May 07, 2013 2:19 PM
Subject: Re: Language editing
...
You are correct if only considering the mail standards. I suspect
that a serious attempt at formal verification would have thrown
up an inconsistency between the set of mail-related standards and
the URI standard. However, I think the underlying problem here is
that we ended up defining the text representation of IPv6 addresses
in three different places, rather than having a single normative
source. (ABNF in the mail standards, ABNF in the URI standard,
and English in ipv6/6man standards.)
(Formal verification of implementation
compliance to the standards would of course have prevented Apple's client
bug,
but that's a very different thing.)
You are, however, correct that this has nothing to do with specification
editing.
Ned
I'm not so sure about that. To me this seems to be a case of
inappropriate use of MUST. First a reminder from RFC 2119:
In particular, they MUST only be used where it is
actually required for interoperation or to limit behavior which has
potential for causing harm (e.g., limiting retransmisssions)
The prohibition against using :: more than once is amply motivated.
Multiple occurrances would introduce ambiguities, so that prohibition
clearly warrants a MUST.
The prohibition against using :: for a single 0 seems to lack
such an obvious syntactic / semantic motivation. Does anyone
remember why this syntactic limitation was added?
Randy